Chapter 32 Percutaneous Lumbar Restabilization via a Posterolateral Approach

Minimally invasive percutaneous lumbar restabilization via a posterolateral approach is a valid and less aggressive procedure than conventional open surgery for the treatment of lumbar segmental insufficiency (LSI) or micro-instability. The potential for performing a percutaneous lumbar restabilization has been made possible by the development of a new expandable titanium device available in several sizes (B-Twin System [Disc-O-Tech Medical Technologies Ltd., Herzliya, Israel] or intervertebral holder [IVH]), which should serve as the first device of its nature in a series of new-generation implants conceived for the less invasive treatment of a number of spine conditions [1–5].

The advantages of this surgical option include the following:

The procedure is performed with use of local anesthesia and minimal sedation if necessary (with an anesthesiologist standing by).

It minimizes iatrogenic lesions by avoiding the intraspinal route and paravertebral muscle trauma.

It does not exclude the use of other percutaneous restabilization techniques, and if necessary, more standard procedures can be carried out in a second step or stage.

It represents an optimization of stand-alone interbody fusion concepts.

It allows for quick mobilization and recovery and, therefore, prompt physiotherapeutic adjuvant treatment and a faster return to normal daily life.

The primary indication for percutaneous lumbar restabilization with the expandable interbody device is the treatment of lumbar segmental instability at the lower lumbar level (Fig. 32-1). This clinical feature is characterized by typical signs and symptoms associated with clear radiologic criteria (Table 32.1).

Figure 32–1 Characteristics of the B-Twin Intervertebral Holder system (Disc-O-Tech Medical Technologies Ltd., Herzliya, Israel) (IVH). The titanium expandable device is used for percutaneous lumbar restabilization procedures. The IVH can be inserted as a 5-mm-diameter tube (A) and then expanded up to 15 mm in diameter (B) assuming a lordotic shape within the intervertebral space. Note the greater contact surface at the level of the end plates on x-ray (C) and schematic drawing (D).

Table 32.1 Clinical and Radiologic Features of Lumbar Segmental Insufficiency (LSI)

Clinical Features
Clinical anamnesis	Mechanical lumbar pain that increases with physical stress and decreases with rest Episodes of hyperalgic blocks that are triggered by certain positions or postures (e.g., prolonged sitting or standing) or specific movements, such as flexion/rotation or flexion-extension
Clinical characteristics	Single- or multiple-segment pain at the level of the interspinous ligaments and/or facet joints produced in hyperextension and/or rotation The patient presents a disharmonic flexion-extension

Pathognomonic Radiologic Signs’
Conventional radiography	Sintering of the disc space (reduction of the disc height) Retrolisthesis or pseudolisthesis Vacuum phenomenon of the disc Macnab sign
Functional x-ray study	Dynamic sagittal instability (flexion-extension > 6 mm)
Magnetic resonance imaging: the stage or degree of LSI and with regard to the Modic changes described below	Local kyphosis and/or posterior articular subluxation on both T1-weighted and T2-weighted sequences
Modic changes	Type I: Disruption and fissuring at the level of the end plates with low signal on T1-weighted images and increased signal on T2-weighted images
	Type II: Fatty conversion with increased signal on T1-weighted images and isointense or increased signal on T2-weighted images
	Type III: Marked sclerosis (osteochondrosis) with low or no signal on both T1- and T2-weighted images

’ To confirm the diagnosis of LSI, the patient must exhibit at least three of the radiologic signs or criteria listed in this table in addition to the standard clinical signs and corresponding anamnesis.

This surgical option may also be contemplated in the treatment of patients with failed back surgery syndrome if no decompression of the nerve roots or foramen is required and if there is no recurrent disc herniation. There is strong evidence that the device offers distraction by “jacking up” the segment, leading to a restabilization of the instable segment. The device also serves as an internal “strengthener” for the fusion process. There is an immediate reduction of the hypermobility contributing to the clinical indication of micro-instability, which is favorable for the fusion process over the months following surgery.

In cases of LSI, the disc of the mobile segment is often the cause of the degeneration of the segment (comprising the two adjacent vertebrae and the disc in between). Thus pain relief can be achieved by immediate restabilization with the device, and the pain relief can be maintained long term owing to the longer, definite bony fusion produced (spondylodesis).

Indications and Contraindications

See Table 32.1 for the indications for percutaneous lumbar restabilization via a posterolateral approach. Box 32.1 lists the contraindications. Degree of disc removal remains a matter of debate because the surgeon is limited as to the degree of motion (in-and-out movements and technical limitation to go laterally in the working channel). Eroders cannot be used for the percutaneous application of the device. They are used strictly in the microsurgical reduced open application. The curette and possibly a shaver must be used in the percutaneous technique.

BOX 32.1 Contraindications to Minimally Invasive Percutaneous Lumbar Restabilization via a Posterolateral Approach

Stenosis

Free sequestrated fragment displaced caudally or cranially in the spinal canal

Listhesis

Acute or rapidly progressing neurologic deficits

Extreme epidural and peridural fibrosis that may first require a epidurolysis